The present invention generally relates to screens for covering a light source. More particularly, the present invention relates to a device for directing light from a source and enhancing lighting effects.
Directional screens are generally known for collimating light and other emissions. In the field of lighting, directional screens are used for collimating light from a source toward a desired direction. Additionally, some directional screens are configured to prevent or reduce glare effects. Furthermore, directional screens are used create an indirect lighting effect, for preventing glare or for aesthetic reasons.
In addition to serving the purpose of optimizing lighting effects, a directional screen can also serve the purpose of protecting the light source, particularly against moisture and dirt. The more that a directional screen surrounds the light source, the better the screen protects the light source.
A drawback of directional screens is that they reduce the light yield of from a light source. Conventional directional screens have strips or lamellae elements which are arranged in a spaced parallel assembly or in a grid. Light passes through air spaces between these lamellae elements. The lamellae elements necessarily have a thickness and, therefore, block light. This efficiency is dependent on the ratio of overall cross-sectional area of the lamellae to the total radiation-transmitting area.
On one hand, it is desirable to minimize the lamellae thickness in order to minimize the loss of light from the source. On the other hand, structural integrity is sacrificed in a grid of thin lamellae, which result in a flimsy directional screen assembly.
In an attempt to overcome such disadvantages, it is known to fill the space between lamellae with a suitable light-transmissive or radiation-transmission material. However, in directional screens of this type, undesirable mirrorings or non-diffuse reflections occur at the lamellae. A further disadvantage of such screens is that it is possible to look between the lamellae onto the light source.
Conventional techniques for manufacturing directional screen components are generally uneconomical. For example, the light-transmissive elements, are typically manufactured by cut and milled from panels of material such as acrylic glass. This is inefficient and considerably diminishes the economical benefit of such a structure. Furthermore, such a process is messy.
It is desirable to provide a directional screen for dispersing a greater amount of light from a source toward one general direction than in an opposite direction. For example, it is desirable to direct light from a ceiling light fixture generally downward to illuminate the room below.
Also, it is desirable to provide an efficient method of coloring the light emitted from a source. With known devices, coloring of light has been achieved with filters, resulting substantial light losses.
Finally, indirect lighting, i.e. illumination of an area by reflecting light from a surface such as a ceiling or wall, ha not adequately been achieved with prior art directional screens where florescent tubes are used as the light source. It has been difficult to overcome design hurdles such as low ceiling environments and the desirability to avoid casting shadows from the fittings required for fluorescent tubes.